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Dionigi F, Weber CC, Primbs M, Gocyla M, Bonastre AM, Spöri C, Schmies H, Hornberger E, Kühl S, Drnec J, Heggen M, Sharman J, Dunin-Borkowski RE, Strasser P. Controlling Near-Surface Ni Composition in Octahedral PtNi(Mo) Nanoparticles by Mo Doping for a Highly Active Oxygen Reduction Reaction Catalyst. Nano Lett 2019; 19:6876-6885. [PMID: 31510752 DOI: 10.1021/acs.nanolett.9b02116] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report and study the translation of exceptionally high catalytic oxygen electroreduction activities of molybdenum-doped octahedrally shaped PtNi(Mo) nanoparticles from conventional thin-film rotating disk electrode screenings (3.43 ± 0.35 A mgPt-1 at 0.9 VRHE) to membrane electrode assembly (MEA)-based single fuel cell tests with sustained Pt mass activities of 0.45 A mgPt-1 at 0.9 Vcell, one of the highest ever reported performances for advanced shaped Pt alloys in real devices. Scanning transmission electron microscopy with energy dispersive X-ray analysis (STEM-EDX) reveals that Mo preferentially occupies the Pt-rich edges and vertices of the element-anisotropic octahedral PtNi particles. Furthermore, by combining in situ wide-angle X-ray spectroscopy, X-ray fluorescence, and STEM-EDX elemental mapping with electrochemical measurements, we finally succeeded to realize high Ni retention in activated PtNiMo nanoparticles even after prolonged potential-cycling stability tests. Stability losses at the anodic potential limits were mainly attributed to the loss of the octahedral particle shape. Extending the anodic potential limits of the tests to the Pt oxidation region induced detectable Ni losses and structural changes. Our study shows on an atomic level how Mo adatoms on the surface impact the Ni surface composition, which, in turn, gives rise to the exceptionally high experimental catalytic ORR reactivity and calls for strategies on how to preserve this particular surface composition to arrive at performance stabilities comparable with state-of-the-art spherical dealloyed Pt core-shell catalysts.
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Affiliation(s)
- F Dionigi
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - C Cesar Weber
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - M Primbs
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - M Gocyla
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - A Martinez Bonastre
- Johnson Matthey Technology Centre , Blount's Court , Sonning Common, Reading RG4 9NH , United Kingdom
| | - C Spöri
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - H Schmies
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - E Hornberger
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - S Kühl
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
| | - J Drnec
- European Synchrotron Radiation Facility , ID 31 Beamline, BP 220, Cedex F-38043 Grenoble , France
| | - M Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - J Sharman
- Johnson Matthey Technology Centre , Blount's Court , Sonning Common, Reading RG4 9NH , United Kingdom
| | - R Edward Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - P Strasser
- The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division , Technical University Berlin , 10623 Berlin , Germany
- Ertl Center for Electrochemistry and Catalysis , Gwangju Institute of Science and Technology , Gwangju 500-712 , South Korea
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Dionigi F, Nielsen MG, Pedersen T, Hansen O, Chorkendorff I, Vesborg PCK. A transparent Pyrex μ-reactor for combined in situ optical characterization and photocatalytic reactivity measurements. Rev Sci Instrum 2013; 84:103910. [PMID: 24182132 DOI: 10.1063/1.4826495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A new Pyrex-based μ-reactor for photocatalytic and optical characterization experiments is presented. The reactor chamber and gas channels are microfabricated in a thin poly-silicon coated Pyrex chip that is sealed with a Pyrex lid by anodic bonding. The device is transparent to light in the UV-vis-near infrared range of wavelengths (photon energies between ~0.4 and ~4.1 eV). The absorbance of a photocatalytic film obtained with a light transmission measurement during a photocatalytic reaction is presented as a proof of concept of a photocatalytic reactivity measurement combined with in situ optical characterization. Diffuse reflectance measurements of highly scattering photocatalytic nanopowders in a sealed Pyrex μ-reactor are also possible using an integrating sphere as shown in this work. These experiments prove that a photocatalyst can be characterized with optical techniques after a photocatalytic reaction without removing the material from the reactor. The catalyst deposited in the cylindrical reactor chamber can be illuminated from both top and bottom sides and an example of application of top and bottom illumination is presented.
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Affiliation(s)
- F Dionigi
- CINF, Department of Physics, Building 312, Fysikvej, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
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Ferrari A, Sgarella A, Zonta S, Scotti-Foglieni A, Grasso D, Dionigi F, Della Valle A, Bombelli E, De Martino M, Trotti E. 589 Minimally Invasive Nipple Sparing Mastectomy – One Year Monoinstitutional Experience of a Novel Technique. Eur J Cancer 2012. [DOI: 10.1016/s0959-8049(12)70654-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Campi F, Dionigi F. Non-invasive measurement of water content in lung phantom by neutrons: latest improvements to the technique. Health Phys 2001; 81:704-710. [PMID: 11725890 DOI: 10.1097/00004032-200112000-00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The novel technique for measuring the water content in lungs based on the slowing down of fast neutrons has been improved making possible its clinical use on patients. This goal has been reached by performing computer simulations that closely mimic the experimental setup and by acquiring a new set of measurements obtained with a plutonium-beryllium (Pu-Be) neutron source provided of an activity suitable to clinical requirements. Finally, accurate radiation dose measurements have been carried out to ensure the acceptability of the technique.
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Affiliation(s)
- F Campi
- Department of Nuclear Engineering, Polytechnic of Milan, Milano, Italy.
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